Method for making disposable tubular device

ABSTRACT

A method of making a disposable tubular device comprising extruding a first material through a first die to form the tube and moving the tube through the second die while extruding a second material through the second die to form the tube-support structure. The second material has a surface hardness which is greater than the surface hardness of the first material.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of Ser. No. 222,109 U.S. Pat. No.5,460,619, filed Apr. 4, 1994 now U.S. Pat. No. 5,460,619.

BACKGROUND OF THE INVENTION

This invention relates to disposable tubular devices of the type usedwith medical instruments for delivering fluid to or evacuating fluidfrom a patient.

Tubular devices for transporting fluids between a patient and a medicalinstrument are typically used by medical professionals such asphysicians, dentists and dental technicians, and veterinarians forsuctioning fluid from or irrigating a part of a patient's body. One suchtubular device is a disposable syringe tip for an air-water dentalsyringe.

A typical syringe tip has a central water passageway and at least onepassageway through which air may flow. The tip is typically sealinglyretained in a syringe hand-piece by a retaining collar which compressesan O-ring against the tip to seal the connection between the tip and thehandpiece. Between uses of the syringe, the tip must be removed from thehand-piece by wholly or partially disengaging the retaining collar. Thetip is then either sterilized before reuse or discarded and replacedwith a new syringe tip.

A disadvantage encountered with prior syringe tip designs is thedifficulty in having a quickly detachable tip which provides awater-tight seal between the central water passageway of the tip and awater conduit of the hand-piece. In some syringes, no elastomeric sealis placed between the water conduit and the central water passageway. Insuch syringes, water may leak between the conduit and the tip. In otherconventional syringes, O-rings are positioned between the end of the tipand the water conduit of the hand-piece. With these syringes, the O-ringis repeatedly used until the O-ring fails, which may be at aninopportune time. Also, unless the O-ring is squeezed between thehand-piece and the tip, the O-ring will not prevent leakage. Further,the force of water from the conduit tends to unseat the tip from theO-ring.

SUMMARY OF THE INVENTION

Among the several objects of this invention may be noted the provisionof an improved tubular device for conveying fluid between a medicalinstrument and a patient; the provision of such a device which isadapted for self-sealing to a fluid conduit of the medical instrument;the provision of such a device which is easily attached to and detachedfrom the medical instrument; the provision of such a device which isdisposable; and the provision of such a device which is of relativelysimple and inexpensive construction.

Generally, a disposable tubular device of this invention is adapted forreleasable and sealing connection to a medical instrument fortransporting fluid between a patient and the instrument. The instrumenthas a nipple with a fluid passageway therethrough. The device comprisesa generally pliable elongate tube of resilient material extendingsubstantially the entire length of the device and a tube-supportstructure extending substantially the entire length of the tube. Thetube has a proximal end configured to be slidably pushed onto the nippleof the medical instrument to a position in which the nipple fits snuglyinside the proximal end of the tube, a distal end, and an elongate fluidpassageway extending through the tube from its proximal end to itsdistal end. The elongate fluid passageway is adapted to communicate withthe fluid passageway of the nipple when the proximal end of the tube ison the nipple. The tube is sufficiently pliable to expand radiallyoutwardly at its proximal end when the proximal end is pushed on thenipple and is sufficiently resilient to form a continuous seal aroundthe nipple for sealing against the fluid leakage between the nipple andthe tube when fluid flows through the passageways. The tube-supportstructure has a stiffness greater than that of the tube and sufficientto maintain the tube in a selected operative position.

Generally, a method of making a disposable tubular device in accordancewith the present invention comprises extruding a first material througha first die to form the tube and moving the tube through a second diewhile extruding a second material through the second die to form thetube-support structure. The second material has a durometer hardnessreading which is greater than the durometer hardness reading of thefirst material at such temperature.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a dental syringe of the presentinvention, with portions broken away to show detail;

FIG. 2 is a side elevational view of a syringe tip of the syringe ofFIG. 1, with portions broken away to show detail;

FIG. 3 is an end elevational view of the syringe tip of FIG. 2 showingcoaxial inner and outer tubes with a central water passageway throughthe inner tube and a plurality of air passageways defined by the innerand outer tubes;

FIG. 4 is a vertical sectional view taken along the plane of line 4—4 ofFIG. 2;

FIG. 5 is an end elevational view a tubular device of the presentinvention similar to the syringe tip of FIGS. 2-4 but having the airpassageways defined by coaxial intermediate and outer tubes;

FIG. 6 is an end elevational view of a tubular device of the presentinvention similar to the syringe tip of FIGS. 2-4 but having the airpassageways defined entirely by the outer tubes;

FIG. 7 is an end elevational view of a tubular device of the presentinvention similar to the syringe tip of FIGS. 2-4 but having only oneair passageway which is generally annular in cross-section and coaxialwith the water passageway;

FIG. 8 is an end elevational view showing a tubular device of thepresent invention similar to the syringe tip of FIGS. 2-4 but havingonly a single fluid passageway;

FIG. 9 is an end elevational view showing a tubular device of thepresent invention similar to the device of FIG. 8 but having threeside-by-side fluid passageways in the inner tube of the tubular device;and

FIG. 10 is an end elevational view showing a tubular device of thepresent invention similar to the device of FIG. 9 but having three fluidpassageways radially disposed in the inner tube of the tubular device.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, and first, more particularly to FIG. 1, amedical instrument of the present invention in the form of an air-waterdental syringe is indicated in its entirety by the reference numeral 20.The dental syringe 20 comprises a conventional hand-piece, generallydesignated 22, a disposable syringe tip, generally designated 24, and asyringe tip coupler, generally designated 26, connecting the syringe tipto the hand-piece.

The hand-piece 22 includes a first fluid (water) conduit 28 fordirecting a stream of water to a discharge end 30 of the hand-piece anda second fluid (air) conduit 32 for directing an air stream to thedischarge end of the hand-piece. The hand-piece 22 further includes athreaded bore 34 at its discharge end 30 for threadably receiving thesyringe tip coupler 26. The water and air conduits 28, 32, respectively,of the hand-piece 22 extend from pressurized sources (not shown) to thebore 34 of the hand-piece and are in fluid communication therewith.

The syringe tip 24 comprises a generally pliable elongate inner tube 36of resilient material extending substantially the entire length of thetip and an outer tube 38, constituting an inner tube support structure,extending substantially the entire length of and surrounding the innertube (FIG. 2). The inner tube 36 has a proximal end 40, a distal end 42,and an elongate fluid passageway 44 extending through the inner tubefrom its proximal end to its distal end. The inner tube has a flutedouter surface 45 with six elongate flutes 46 equally spaced about thecircumference of the outer surface, and six elongate outer surfaceportions 48 each between adjacent flutes. The flutes 46 and outersurface portions 48 extend the length of the inner tube 36. The innertube 36 fits snugly within the outer tube 38 and each elongate outersurface portion 48 is in continuous contact with the inner surface 50 ofthe outer tube generally along the entire length of the inner tube.Preferably, the inner and outer tubes 36, 38, respectively, are heldtogether by a close friction fit between the outer surface portions 48of the inner tube and the inner surface 50 of the outer tube.Alternatively, the tubes 36, 38 may be bonded together, e.g., by heat orwith a suitable adhesive. The flutes 46 and the inner surface 50 of theouter tube 38 define six elongate air passageways 52 circumferentiallydisposed about the elongate fluid passageway 44 (i.e., the central waterpassageway) and extending substantially the length of the tube.Preferably, the inner and outer tubes 36, 38 have generally coterminousproximal and distal ends (FIG. 2). Also preferably, the syringe tip 24has a generally uniform cross-section (FIG. 4) throughout its entirelength and its proximal end 40 (FIG. 3) is substantially the same as itsdistal end 42. Although the flutes 46 in this embodiment are in theouter surface 45 of the inner tube 36, it is to be understood that theflutes may alternatively be formed on the inner surface 50 of the outertube 38 and still be within the scope of the present invention.

The syringe tip coupler 26 comprises a cylindric stem 54 having firstand second externally threaded surface portions 56, 58, respectively,adjacent opposite ends 60, 62 of the stem, and a central bore 64 forreceiving the syringe tip 24. The first threaded surface portion 56 isthreadably fitted within the threaded bore 34 of the hand-piece 22. Thesecond threaded surface portion 58 receives a nut 66 which maintains thesyringe tip 24 in the central bore 64. The stem 54 further includes aforwardly projecting nipple 65 within the central bore 64 for receivingthe proximal end 40 of the inner tube 36, a rearwardly projecting nipple68 aligned with the forwardly projecting nipple and receivable withinthe water conduit 28 of the hand-piece 22, and a longitudinal opening 70through the nipples for passage of water from the water conduit throughthe aligned nipples and into the central water passageway 44 of theinner tube 36. The central bore 64 is in fluid communication with theair conduit 32 by way of a radially directed opening 72 in the stem 54.A first O-ring 74 is positioned generally between the stem 54 and thehand-piece 22 circumferentially about the rearwardly projecting nipple68 for sealing against water leakage between the water conduit 30 andthe stem.

The syringe tip 24 is adapted for releasable and sealing connection tothe stem 54. The proximal end 40 of the inner tube 36 is configured tobe slidably pushed onto the forwardly projecting nipple 65 of the stem54 so that the nipple fits snugly inside the proximal end of the innertube (FIG. 1). The elongate water passageway 44 of the inner tube 36communicates with the longitudinal opening 70 of the nipple 65 when theproximal end of the tube is positioned on the forwardly projectingnipple. To this end, the inner tube 36 is sufficiently pliable so thatits proximal end 40 expands radially outwardly when pushed onto thenipple 65 and sufficiently resilient to form a continuous seal aroundthe nipple for sealing against fluid leakage between the nipple and theinner tube when water flows through the passageways 30, 44. Because theinner tube 36 seals against the nipple 65, it is unnecessary to providean O-ring between the inner tube and nipple.

As noted above, the syringe 24 is releasably secured to the syringe tipcoupler 26 of the medical instrument 20 by the nut 66. A second O-ring76 is circumferentially positioned over the outer surface 78 of theouter tube 38 and abuts a forward end 62 of the stem 54 to preventleakage of air between the tip 24 and stem. Tightening the nut 66 urgesa generally cone-shaped, split collar 82 against the second O-ring 76 tohold the O-ring in place against the stem 54 and also squeezes thecollar radially inwardly against the syringe tip 24 to thereby hold thesyringe tip in place. A third O-ring 84 is circumferentially positionedaround the stem 54 generally between the first and second threadedsurface portions 56, 58, respectively, and between the nut 66 andhand-piece 22 to prevent leakage of air from between the stem andhand-piece. Preferably, the coupler 26 is configured so that the syringetip 24 may be inserted into and removed from the stem 54 by looseningthe nut 66 without the need to remove the nut.

The inner tube 36 of the syringe tip 24 is preferably made of a pliantmedical grade polyvinyl chloride or other suitable synthetic resinhaving a durometer hardness reading between approximately 80 Shore A and90 Shore A. Within this range, the inner tube is sufficiently pliable toseal against water leakage and sufficiently stiff to prevent the airpassageways 52 from being pinched closed when the inner tube engages thenipple 65 of the stem 54 or when the syringe tip is bent to the degreeshown in FIG. 2. The outer tube 38 (i.e., the tube-support structure) ispreferably made of a stiffer medical grade polyvinyl chloride, having adurometer hardness reading of at least approximately 60 Shore D (mostpreferably 81 Shore D) and a flex modulus of at least approximately10,000 psi (most preferably 12,000 psi). The outer tube 38 thus has astiffness greater than that of the inner tube 36 and sufficient tomaintain the entire syringe tip 24 in a selected operative position.Preferably, the outer tube 38 is sufficiently flexible to be capable ofbeing bent by the operator to a selected operative position (FIG. 2).The outer tube 38 is also sufficiently stiff (i.e., resistant tobending) such that the force of the fluid streams passing through thetip 24 during use do not substantially alter the shape the angle of thebend) of the tip. Because of this stiffness, a stream of air or water,or a mixed stream of both, can be directed to the specified desiredlocation. Because the inner and outer tubes are both of polyvinylchloride, there is an inherent adhesion between the tubes which resistsmovement of the inner tube relative to the outer tube. Although thetubes are preferably formed of polyvinyl chloride, it is to beunderstood that the tubes could be formed of other suitable resinswithout departing from the scope of this invention.

A disposable tubular device of the present invention (e.g., the syringetip 24) is preferably made by a dual-extrusion method. A first materialis extruded through a first die to form an inner tube 36. This die isconfigured such that extrusion of the first material through the firstdie forms an elongate tube with elongate flutes. The flutes extend alongsubstantially the entire length of the tube. The fluid tube is thenpassed longitudinally through a second die while a second material isextruded through the second die and around the inner tube. The extrudedtubes are then cut to length to form the tip 24. The second die isconfigured so that the outer tube 38 (sleeve) so formed fits snugly overthe inner tube 36. The sleeve 38 constitutes a tube-support structurefor maintaining the general overall shape of the inner tube 36. Theflutes 46 and a portion of an inner surface 50 of the sleeve 38 define aplurality of fluid passageways 52. The first and second materials areselected so that the outer tube of the tip 24 is stiffer than the innertube at the typical operating temperatures of the syringe (e.g.,temperatures in the range of 50° F. to 110° F.).

In use, the syringe tip coupler 26 is mated with the hand-piece 22 ofthe dental syringe 20 as previously described. The syringe tip 24 isinserted into the central bore 64 of the coupler 26 and slidably pushedonto the forwardly projecting nipple 65 of the coupler 26 to releasablyand sealably mount the tip of the medical instrument 20. Preferably, thesyringe tip 24 is provided to the operator with a bend therein. The bendcauses fluid to be sprayed at an angle and also helps retain the innertube within the outer tube. The operator may vary the angle of the bend(or remove it entirely) to facilitate the spraying of fluid at adifferent angle. The relatively stiff outer tube 38 ensures that theforce of the fluid streams passing through the tip 24 during use doesnot substantially alter the shape (e.g., the length of the bend) of thetip. Because of this stiffness, a stream of air or water, or a mixedstream of both, can be directed to the specified desired location. Theoperator selects the fluid stream or combination of fluid streams (e.g.,air, water, or an air-water mixture) to be delivered to the patient. Thewater stream, if selected, flows from the pressurized source through thewater conduit 28 of the hand-piece into the longitudinal opening 70 ofthe stem 54. The water then passes into the central water passageway 28of the syringe tip 24 mounted on the forwardly projecting nipple 65 atits proximal end 40. The water is discharged from the distal end 42 ofthe inner tube 36 at the desired location. The resilient inner tube 36prevents water leakage between the forwardly projecting nipple 65 andthe inner tube as long as part of the nipple is within the inner tube.Thus, the inner tube will prevent leakage even if the tip is not fullypushed onto the nipple. Also, because of the resilient inner tube 36,the tip 24 seals against the nipple even when the tip is not tightlyheld on the nipple. Thus, the tip may be turned or rotated on the nipplewithout leakage. The air stream, if selected, flows from the pressurizedsource through the air conduit 32 of the hand-piece 22 into the centralbore 64 of the stem 54 by way of the radially directed opening 72 in thestem 54. The pressurized air passes from the central bore 64 into theair passageways 52 of the tip 24 which are in fluid communication withthe central bore. The air is discharged from the distal end 42 of thesyringe tip 24 to atomize the water discharged from the inner tube 36.

After use, the syringe tip 24 is removed from the coupler 26 bydisengaging the tip from the nipple 65. This is done by simply looseningthe nut and pulling the tip 24 from the medical instrument 20. The tip24 is then discarded. A new syringe tip 24 can be inserted into thecoupler 26 for the next use of the medical instrument 20.

An alternative embodiment of a disposable syringe tip of the presentinvention, generally designated 86, is shown in FIG. 5. The tip 86comprises an inner tube 88, an outer tube 90, and an intermediate tube92 positioned between the inner and outer tubes. Preferably, all threetubes 88, 90, 92 have coterminous proximal and distal ends and generallyuniform cross-sections throughout the entire length of the tip 86. Thetip 86 has a central water passageway 94 defined by the inner tube 88.The intermediate tube 92 has inner and outer surfaces 98, 100,respectively. The inner surface 98 of the intermediate tube 92 opposesthe outer surface 102 of the inner tube 88 and the outer surface 100 ofthe intermediate tube opposes the inner surface 104 of the outer tube90. The outer surface 100 of the intermediate tube 92 comprises a flutedsurface 106 similar to the flutes 46 of the inner tube 36 of the tip inFIGS. 2-4. The flutes 106 of the intermediate tube 92 and a portion ofthe inner surface 104 of the outer tube 90 define air passageways 108extending the length of the intermediate tube. In this embodiment,either or both the intermediate and outer tubes 90, 92 may be made of agenerally stiff material and constitute the tube-support structure, andthe inner tube 88 comprises a generally pliable elongate tube ofresilient material (similar to inner tube 36) extending substantiallythe entire length of the tip 86. The inner tube 88 fits snugly withinthe intermediate tube 92. The outer surface portion 110 of theintermediate tube 92 is in continuous contact with the inner surface 104of the outer tube 90 generally along the entire length of the tip 86. Itis to be understood that the inner surface 98 of the intermediate tube92 may be configured with the fluted surface 106, or that the outersurface 102 of the inner tube 88 or inner surface 104 of the outer tube90 may be formed with the flutes and still be within the scope of thepresent invention.

Referring now to FIG. 6, another embodiment of a syringe tip of thepresent invention is generally designated 112. The tip 112 comprises aninner tube 114 and an outer tube 116 preferably having coterminousproximal and distal ends and generally uniform cross-sections throughoutthe entire length of the tip 112. A central water passageway 122 isdefined by the inner tube 114, and three air passageways 124, disposedradially outwardly of the water passageway, are defined entirely by theouter tube 116. Both the water and air passageways 122, 124 of the tubes114, 116 extend the entire length of the tip 112. In this embodiment,the outer tube 116 is made of a generally stiff material and constitutesthe tube-support structure and the inner tube 114 comprises a generallypliable elongate tube of resilient material. The inner tube 114 fitssnugly within the outer tube 116 and the outer surface 126 of the innertube 114 is in continuous contact with the inner surface 128 of theouter tube 116 generally along the entire length of the tip 114.Preferably, the inner and outer tubes 114, 116 are held together by aclose friction fit, and the materials of the tubes are selected forproviding an inherent adhesion of the inner tube to the outer tube.Alternatively, the tubes 114, 116 may be bonded together by heat or witha suitable adhesive.

Referring to FIG. 7, another embodiment of a syringe tip of the presentinvention, generally designated 130, comprises an inner tube 132 and anouter tube 134 preferably having coterminous proximal and distal endsand generally uniform cross-sections throughout the entire length of thetip. The tip 130 has a central water passageway 140 defined by the innertube 132 and an air passageway 136 formed to be generally coaxial withrespect to the water passageway. To this end, the outer tube 134 isradially spaced from the inner tube 132 to create an annulus (i.e., theair passageway 136) between the inner and outer tubes extending thelength of the tip 130. The inner tube 132 is retained within the outertube 134 due to the syringe tip being bent at a region along the lengthof the syringe tip. In this embodiment, the outer tube 134 constitutesthe generally stiff tube-support structure and the inner tube 132comprises a generally pliable elongate tube of resilient material.

In FIG. 8, another embodiment of a tubular device, generally designated142, comprises a generally pliable elongate inner tube 144 of resilientmaterial and an outer tube 146 constituting the tube-support structure.Preferably, the inner and outer tubes 144, 146 have coterminous proximaland distal ends and generally uniform cross-sections throughout theentire length of the tip 142. The inner tube 144 comprises a generallypliable elongate tube of resilient material and is formed with a centralsingle fluid passageway 152. The inner tube 144 fits snugly within theouter tube 146 which constitutes the generally stiff tube-supportstructure. The outer surface 154 of the inner tube 144 is in continuouscontact with the inner surface 156 of the outer tube 146 generally alongthe entire length of the nip 142. The single passageway embodiment 142of the tubular device is particularly useful for suctioning fluid from apatient.

As shown in FIGS. 9 and 10, other embodiments of the tubular device forconveying one or more fluids comprise a multi-lumen inner tube 158having a plurality of coextensive passageways 160 extending the entirelength of the tube. In one embodiment (FIG. 9), generally designated162, the passageways 160 are arranged side-by-side. In the otherembodiment (FIG. 10), generally indicated at 164, the passageway 160 arecircumferentially disposed in the inner tube 158. The inner tube 158 ofeach embodiment of the tubular devices 162, 164 comprises a generallypliable elongate tube of resilient material and is surrounded by agenerally stiff outer tube 166 which constitutes the tube supportstructure. The inner tube 158 fits snugly within the outer tube 166 andthe outer surface 168 of each inner tube 158 is in continuous contactwith the inner surface 170 of each outer tube 166 generally along theentire length of the tubular device 162, 164. The wall thickness of theinner tube 158 is sufficient to allow the inner tube 158 to adequatelyyield in order to accept mating nipples of the medical instrument (notshown) to which it connects. The multiple lumens may be used to directmultiple fluids to a patient, or to direct fluid through one lumen whileevacuating fluid through another.

Although the tubular devices are described herein as being syringe tipsfor dental syringes, it is to be understood that tubular devices of thepresent invention may have uses in various other aspects of the medicalfield.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:
 1. A method of making a disposable tubular device adapted for releasable and sealing connection to a medical instrument for transporting fluid between a patient and the instrument, the instrument having a nipple for engagement with the tubular device, the device comprising a pliable elongate tube of resilient material and a tube-support structure having a stiffness greater than that of the tube and extending substantially the entire length of the tube, the tube and tube-support structure forming at least two distinct passageways, a first of the two passageways being formed by the tube and a second of the two passageways being formed by the tube and the tube-support structure, the method comprising: extruding a first material through a first die to form the tube, the said first material being sufficiently pliable to form a seal around the nipple for sealing against fluid leakage between the nipple and the tube; moving the tube through a second die while extruding a second material through the second die to form the tube-support structure; the second material having a surface hardness which is greater than the surface hardness of the first material.
 2. A method as set forth in claim 1 wherein the second die is configured to form a sleeve around the tube, the sleeve comprising the tube-support structure.
 3. A method as set forth in claim 2 wherein the first die is configured such that step of extruding the first material through the first die forms the tube with a fluted outer surface having elongate flutes, the flutes extending along substantially the entire length of the tube.
 4. A method as set forth in claim 3 wherein the second die is configured to form the sleeve in a friction fit over the tube, the flutes and an inner surface of the sleeve defining a plurality of fluid passageways.
 5. A method as set forth in claim 1 wherein the first material is a polyvinyl chloride having a durometer hardness reading between approximately 80 Shore A and 90 Shore A.
 6. A method as set forth in claim 5 wherein the second material is a polyvinyl chloride having a durometer hardness reading of at least approximately 60 Shore D.
 7. A method of making a disposable tubular device adapted for releasable and sealing connection to a medical instrument for transporting fluid between a patient and the instrument, the device comprising a pliable elongate tube of resilient material and a tube-support structure having a stiffness greater than that of the tube and extending substantially the entire length of the tube, the tube and tube-support structure forming at least two distinct passageways, the method comprising: extruding a first material through a first die to form the tube, the first material having a durometer hardness reading between approximately 80 Shore A and 90 Shore A; moving the tube through a second die while extruding a second material through the second die to form the tube-support structure in a friction fit over the elongate tube, the second material having a durometer hardness reading of at least approximately 60 Shore D.
 8. A method as set forth in claim 7 wherein the first material and the second material are polyvinyl chloride.
 9. A method as set forth in claim 7 wherein the second die is configured to form a sleeve around the tube, the sleeve comprising the tube-support structure.
 10. A method as set forth in claim 9 wherein the first die is configured such that step of extending the first material through the first die forms the tube with a fluted outer surface having elongate flutes, the flutes extending along substantially the entire length of the tube.
 11. A method as set forth in claim 10 wherein the flutes and an inner surface of the sleeve define a plurality of fluid passageways.
 12. A method for making a disposable tubular device adapted for releasable and sealing connection to a medical instrument for transporting fluid between a patient and the instrument, the instrument having a nipple for engagement with the tubular device, the device comprising a pliable elongate tube of resilient material and a tube-support structure having a stiffness greater than that of the tube and extending substantially the entire length of the tube, the tube and tube-support structure forming at least two distinct passageways, a first of the two passageways being formed by the tube and a second of the two passageways being formed by the tube and the tube-support structure, the method comprising: extruding a first polyvinyl chloride material through a first die to form the tube with a fluted outer surface having elongate flutes extending along substantially the entire length of the tube, the material being sufficiently pliable to form a seal around the nipple for sealing against fluid leakage between the nipple and the tube; moving the tube through a second die while extruding a second polyvinyl chloride material through the second die to form the tube-support structure, the second die being configured to form the tube-support structure in a friction fit over the elongate tube; the second polyvinyl chloride material having a surface hardness which is greater than the surface hardness of the first polyvinyl chloride material.
 13. A method as set forth in claim 12 wherein the first polyvinyl chloride material has a durometer hardness reading between approximately 80 Shore A and 90 Shore A.
 14. A method as set forth in claim 13 wherein the second polyvinyl chloride material has a durometer hardness reading of at least approximately 60 Shore D.
 15. A method of making a disposable tubular device adapted for releasable and sealing connection to a medical instrument for transporting fluid between a patient and the instrument, the instrument having a nipple for engagement with the tubular device, the device comprising a pliable elongate tube of resilient material and a tube-support structure having a stiffness greater than that of the tube and extending substantially the entire length of the tube, the tube and tube-support structure forming at least two distinct passageways, a first of said passageways being formed by the tube and a second of said passageways being formed by the tube and the tube-support structure, the method comprising the steps of forming a first material into the tube and forming a second material into the tube-support structure so the structure has a friction fit with the tube, said first material being sufficiently pliable to form a seal around the nipple for sealing against fluid leakage between the nipple and the tube, said second material having a surface hardness which is greater than the surface hardness of the first material.
 16. A method of making a disposable tubular device adapted for releasable and sealing connection to a medical instrument for transporting fluid between a patient and the instrument, the instrument having a nipple for engagement with the tubular device, the device comprising a pliable elongate tube of resilient material and a tube-support structure having a stiffness greater than that of the tube and extending substantially the entire length of the tube, the tube and tube-support structure forming at least two distinct passageways, a first of the two passageways being formed by the tube and a second of the two passageways being formed by the tube and the tube-support structure, the method comprising: extruding a first material to form the tube, said first material being sufficiently pliable to form a seal around the nipple for sealing against fluid leakage between the nipple and the tube; moving the tube through a die while extruding a second material through the die to form the tube-support structure having a friction fit with the tube; the second material having a surface hardness which is greater than the surface hardness of the first material.
 17. A method as set forth in claim 16 wherein the die is configured to form a sleeve around the tube, the sleeve comprising the tube-support structure.
 18. A method as set forth in claim 17 wherein the step of extruding the first material forms the tube with a fluted outer surface having elongate flutes, the flutes extending along substantially the entire length of the tube.
 19. A method as set forth in claim 16 wherein the first material is a polyvinyl chloride having a durometer hardness reading between approximately 80 Shore A and 90 Shore A.
 20. A method as set forth in claim 19 wherein the second material is a polyvinyl chloride having a durometer hardness reading of at least approximately 60 Shore D. 